Water head
Culvert, screen and outfall manual, (CIRIA C786) published by CIRIA in 2019, defines ‘head’ as: ‘The total energy per unit weight of fluid expressed in metres of water above a datum.’
Head loss is: ‘The difference in head between two points due to friction or other features that result in energy loss (eg a transition, step, construction, expansion or bend).’
Headroom is the: ‘Vertical gap between the water surface and the roof (soffit) of a culvert or outfall to allow for floating debris (also known as air draught).’
Headwater depth is: ‘The depth of water above culvert invert at the culvert inlet.’
Headwater elevation is: ‘The depth of water above datum at the culvert inlet.’
Headwater ratio is: ‘Specific energy of headwater divided by barrel height.’
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Editor's broadbrush view on forms of electrical heating in context.
The pace of heating change; BSRIA market intelligence
Electric Dreams, Boiler Realities.
New President of ECA announced
Ruth Devine MBE becomes the 112th President of the Electrical Contractors Association.
New CIAT Professional Standards Competency Framework
Supercedes the 2019 Professional Standards Framework from 1 May 2025.
Difficult Sites: Architecture Against the Odds
Free exhibition at the RIBA Architecture Gallery until 31 May.
PPN 021: Payment Spot Checks in Public Sub-Contracts
Published following consultation and influence from ECA.
Designing Buildings reaches 20,000 articles
We take a look back at some of the stranger contributions.
Lessons learned from other industries.
The Buildings of the Malting Industry. Book review.
Conserving places with climate resilience in mind.
Combating burnout.
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.